Now Playing: Top social media executives to testify before Congress

Now Playing: Facebook: Russian-linked content may have reached 126 million during 2016 election

Now Playing: Workers across the US show support for actor seen at Trader Joe’s

Now Playing: Nike releases new controversial ad with former NFL quarterback

Now Playing: Plane from Dubai quarantined at JFK due to sick passengers

Now Playing: Tropical Storm Gordon makes landfall in Mississippi

Now Playing: Pickup truck driver rams into TV station in Dallas

Now Playing: What is sepsis?

Now Playing: Cincinnati officer tases 11-year-old girl for shoplifting from a grocery store

Now Playing: Couple accused of blowing money raised for homeless vet ordered to appear in court

Now Playing: Murder-suicide suspect’s sister says she hopes he will ‘rot in hell for what he did’

Now Playing: Kayden Mancuso’s mother: ‘I miss every single little thing about her’

Now Playing: Man arrested after ramming truck into building of Fox affiliate: Police

Now Playing: Social media giants summoned to Capitol Hill

Now Playing: Emirates flight from Dubai lands at JFK Airport with reports of sick passengers

Now Playing: Harrowing body cam footage shows inside of life-threatening 2017 Santa Rosa fire

Now Playing: Bra controversy comes to high school band practice

Now Playing: Authorities investigating reports of flight with up to 100 ill people at NY airport

Now Playing: News headlines today: Sep. 5, 2018

Now Playing: Jury selection begins in Chicago police officer’s murder trial